1. Field of the Invention
The present invention relates to a deflection yoke. In particular, the present invention relates to an apparatus for correcting mis-convergence and geometric distortion in a deflection yoke using a variable resistance in order to have a better control on VCR properties of a product by controlling current in a comma-free state, which is regarded very distinctive from the typical method of attaching a iron plate to a product.
2. Description of the Prior Art
In general, a deflection yoke 10, as shown in FIG. 1, is installed at a neck portion 110 of a cathode-ray tube 100. According to a winding configuration, it is divided into a saddle-saddle type defection yoke as shown in FIGS. 2 and 3, and a saddle-toroidal type deflection yoke as shown in FIGS. 4 and 5. The deflection yoke deflects electron beams emitted from a BGR electron gun 120 installed at the cathode-ray tube in a neck portion 110 to all directions, e.g., the left and right sides, and up and down, thereby making the electron beams collide with a precise position on a fluorescent screen of the cathode-ray tube.
FIGS. 2 and 3 show a saddle-saddle type deflection yoke in accordance with the related art. As shown in the Figures, a saddle type horizontal deflection coil 12a and 12b is installed at the top/bottom of inner periphery of screen portion in a conical-shaped coil separator 11, and a saddle type vertical deflection coil 13a and 13b on the left/right of outer periphery. Electrically, the saddle type deflection coils are serially connected in the order of upper left 13a-1, lower left 13a-2, upper right 13b-1, and lower right 13b-2 (See FIG. 6).
In order to enhance a magnetic field of the vertical deflection coils 13a and 13b, a conical ferrite core 14 is installed at the outer periphery of the screen portion in the coil separator 11. Also, comma-free coil 15 are installed around the outer periphery of a neck portion in the coil separator 11 to improve comma aberration generated by the vertical deflection coils 13a and 13b. 
FIGS. 4 and 5 show a saddle-toroidal type deflection yoke according to the related art. As shown in the figures, a horizontal deflection coil 12 is installed at the upper/lower portion of a inner periphery of a screen in a conical coil separator 11, a conical ferrite core 14 is installed at the outer periphery, and a toroidal type vertical deflection coil 16 is wound around the upper/lower portion of the ferrite core 14.
In addition, around the outer periphery of the neck portion of the coil separator 11, comma-free coils 15 are additionally installed in order to improve a comma aberration generated by the vertical deflection coil 16. The vertical deflection coil 16 is wound around the upper/lower portion of the ferrite core 14.
In case of a saddle-saddle type deflection yoke illustrated in FIGS. 2 and 3, depending on the relative dispersion and/or relative current intensity between the left vertical deflection coil 13a and the right deflection coil 13b, a magnetic field may differ on the left side and the right side. This difference in a magnetic field is main factor that causes mis-convergence and geometric distortion (hereinafter, it is abbreviated as G/D).
Similarly, a saddle-toroidal deflection yoke illustrated in FIGS. 4 and 5, depending on the relative dispersion and/or relative current intensity between the vertical defection coil 16a being wound around the upper left and lower left portion in X and Y-axes and the vertical deflection coil 16b being wound around the upper right and lower right portion, a magnetic field may (differ on the left side and the right side. Again, this difference in a magnetic field causes mis-convergence and G/D on the screen.
There are two types of the mis-convergence, that is, YV mis-convergence and YHC mis-convergence. The YV mis-convergence, as shown in FIGS. 7 and 9, indicates a point where a red horizontal line R crosses a blue horizontal line B at the upper and lower portions of Y-axis on a screen. In the meantime, the YHC mis-convergence, as shown in FIG. 10, indicates a point where a vertical line R and a vertical line B meets each other. The G/D is a state that a screen is distorted from a normal shape (See FIGS. 6a and 13), and in particular, as FIGS. 11 and 13 illustrate, it sometimes does a trapezoid distortion.
FIG. 14 is an auxiliary circuit of YV mis-convergence of the saddle-saddle type deflection yoke illustrated in FIGS. 2 and 3. As shown in the figure, the left vertical deflection coil 13a and the right deflection coil 13b are electrically connected in series. And, to the left/right vertical deflection coils 13a and 13b, connected in parallel is a differential type of distribution circuit comprising two-fixed resistance 21a and 21b and a variable resistance 22.
According to the conventional YV mis-convergence auxiliary circuit in FIG. 14, by adjusting the variable resistance 22 and a magnetic field, which is generated by adjusting relative current intensity in the left vertical deflection coil 13a and the right vertical deflection coil 13b, YV mis-convergence illustrated in FIG. 7 or 9 is corrected as shown in FIG. 8, wherein the line R and the line B are concordant.
FIG. 15 is an auxiliary circuit of YV mis-convergence of the saddle-toroidal type deflection yoke illustrated in FIGS. 4 and 3b. As shown, the upper left vertical deflection coil 16a-1, the lower left vertical deflection coil 16b-1, the upper right vertical deflection coil 16a-2, and the lower right vertical deflection coil 16b-2 are serially connected in order. And, to the vertical deflection coils 16a-1 and 16b-1 wound around the upper left-lower left portion and the vertical deflection coils 16a-2 and 16b-2 wound around the upper right-lower right portion, connected in parallel is a differential type of distribution circuit comprised of two-fixed resistance 21a and 21b and a variable resistance 22.
Similar to the YV mis-convergence auxiliary circuit illustrated in FIG. 14, the conventional YV mis-convergence auxiliary circuit in FIG. 15, by adjusting the variable resistance 22 and a magnetic field of the left/right portion, which is generated by adjusting relative current intensity flowing in the vertical deflection coils 16a-1 and 16b-1 wound around the upper left and lower left portions and the vertical deflection coils 16a-2 and 16b-2 wound around the upper right and lower right portions, corrects the YV mis-convergence illustrated in FIG. 7 or 9 to be the same with that in FIG. 8, that is, the line R and the line B are concordant.
However, in case of a saddle-saddle type and/or a saddle-toroidal type, when YV mis-convergence is corrected by using the variable resistance 22, G/D pattern as well as convergence pattern are changed depending on the differences between the left/right portion magnetic field due to the changes in the relative current intensity flowing in the vertical deflection coil 13a or 16a positioned on the left portion and the vertical deflection coil 13b or 16a positioned on the right portion. Therefore, it is always possible that a new G/D is generated even though YV mis-convergence may have been corrected.
Moreover, G/D can be generated by dispersion difference of the left and the right vertical deflection coils that sometimes occurs during winding. That is, due to the unbalanced wound coil and dispersion difference by a mechanical configuration, it is practically very difficult to wind the coils around 1 through 4 upper portions in X and Y-axes to form a perfectly symmetric magnetic field. Hence, although a mis-convergence shown in FIG. 5 caused by the unbalanced dispersion may have been perfectly corrected, G/D illustrated in FIG. 11 or 13 can be generated. And, as shown in FIG. 12, although G/D can be perfectly corrected, a mis-convergence illustrated in either FIG. 7 or FIG. 9 can be generated at any time. Therefore, the conventional YV mis-convergence auxiliary circuit shown in FIGS. 14 and 15 cannot correct a mis-convergence and G/D at the same time.
On the other hand, in case of the typical deflection yoke used in a television, since the television screen exhibits moving pictures, G/D was not regarded as a critical problem, and convergence was primarily adjusted by using a circuit illustrated in FIGS. 14 and 15. However, in case of a recently developed personal computer, since the monitor has to show accurate still images, a deflection yoke is required to have a more accurate convergence and improved G/D.
In order to meet the requirements described above, a new technique is introduced (See FIG. 17). Here, the vertical deflection on the left portion 13a and the vertical deflection on the right portion 13b are connected in series and the coils 13a and 13b are installed at the left and the right side of outer periphery of the screen portion in a coil separator.
To the left vertical deflection coil 13a and the right deflection coil 13b, connected in parallel is a differential type distribution circuit portion 40. The differential type of distribution circuit portion 40 is comprised of a first fixed resistance R1, a first variable resistance VR1, and a second fixed resistance R1 being connected in series, and a moving electrode end of the first variable resistance VR1 and the first and the second vertical deflection coils being connected to a common contact point.
The differential type distribution circuit portion 40 controls a relative current intensity flowing in the left vertical deflection coil 13a and the right deflection coil 13b, and adjusts G/D on a screen, thereby being called a distortion adjusting portion.
In addition, a first through sixth comma-free coils 51-56 are serially connected to the left and right deflection coils 13a and 13b. The comma-free coils 51-56 are electrically connected in series to each other and simultaneously, as shown in FIGS. 18 and 19, they are wound around the upper left, upper right, lower left, lower right, middle left and middle right portions of outer periphery of a neck portion in the coil separator using an E-shaped magnetic member 58 as a medium, thereby generating 6 electrode magnetic fields to correct comatic aberration.
Unfortunately, the conventional technique described above has a problem of mis-convergence, particularly, in VCR(Vertical Center Raster). In detail, VCR is a vertical mis-convergence involving the center of xe2x80x9cRedxe2x80x9d and xe2x80x9cBluexe2x80x9d and the center of xe2x80x9cGreenxe2x80x9d at the upper and lower portions on the Y-axis.
Since initial value of the VCR is predetermined as adjusting designs and properties of coils for winding, the VCR characteristics are taken into account only deflection yoke properties are concerned, and the VCR of a tube stays the same all the time without any change. However, in some cases, the initial VCR values are dispersed by several variables (e.g., changes of coil dispersion, element dispersion etc.) during a production procedure.
So far, in order to compensate changeability of the VCR, many attempts have been made. One of them was attaching a magnetic member (made of permaloid 5*15*0.5t, 5*20*0.5t) to the upper and lower portions and on the left and right portions of a deflection yoke to adjust VCR (approximately, xc2x10.04 mm).
However, the above-described method takes place after a deflection yoke is completed and additional work for the attachment of the magnetic member has to be done and extra elements like a magnetic member and glue are required.
It is, therefore, an object of the present invention to provide an apparatus for correcting mis-convergence and geometric distortion in a deflection yoke by using a variable resistance in order to have a better control on VCR by adjusting the current flowing in a comma-free coil, without attaching a magnetic member as in a conventional apparatus.
To achieve the above object, an apparatus for correcting a mis-convergence and geometric distortion in a deflection yoke using a variable resistance, comprising a conical-shaped coil separator including a neck portion and a screen section; an upper horizontal deflection coil and a lower horizontal deflection coil installed to be electrically connected to each other at an upper and lower portions of inner periphery of the screen portion in the coil separator; a left vertical deflection coil and a right vertical deflection coil installed to be electrically connected to each other at an upper and lower portions of outer periphery of the screen portion in the coil separator; a conical-shaped ferrite core installed at outer periphery of the screen portion in the coil separator to enhance a magnetic field of the vertical deflection coil;
a plurality of comma-free coils installed at the neck portion of the coil separator to be electrically connected to the vertical deflection coil for generating a pin-cushion magnetic field, thereby canceling a barrel magnetic field generated by the left and right vertical deflection coils; a distortion adjusting portion for correcting geometric distortion on a screen by adjusting a relative current flowing in the left and right vertical deflection coils and thereby, adjusting a relative magnetic field in the left and right sides; a first convergence adjusting portion for correcting a vertical mis-convergence on a screen by adjusting a relative current flowing in the comma-free coils at the middle left portion and the middle right portion and thereby, adjusting a relative magnetic field in the left and right sides; a second convergence adjusting portion for correcting a horizontal mis-convergence on a screen by adjusting a relative current flowing in the comma-free coils at the upper portion and the lower portion and thereby, adjusting a relative magnetic field in the upper and lower sides; and a vertical center raster mis-convergence adjusting portion, comprising variable resistance connected to the comma-free coils in parallel, and fixed resistance connected to a common contact point of the left and right comma-free coils and a moving electrode of the variable resistance.
It is desirable that the variable resistance in the vertical center raster mis-convergence adjusting portion is in a range of from 5 to 10xcexa9.
Also, an apparatus for correcting a mis-convergence and geometric distortion in a deflection yoke using a variable resistance, comprising a conical-shaped coil separator including a neck portion and a screen section; an upper horizontal deflection coil and a lower horizontal deflection coil installed to be electrically connected to each other at an upper and lower portions of inner periphery of the screen portion in the coil separator; a left vertical deflection coil and a right vertical deflection coil installed to be electrically connected to each other at an upper and lower portions of outer periphery of the screen portion in the coil separator; a conical-shaped ferrite core installed at outer periphery of the screen portion in the coil separator to enhance a magnetic field of the vertical deflection coil; a plurality of comma-free coils installed at the neck portion of the coil separator to be electrically connected to the vertical deflection coil for generating a pin-cushion magnetic field, thereby canceling a barrel magnetic field generated by the left and right vertical deflection coils; a first convergence adjusting portion for correcting a vertical mis-convergence on a screen by adjusting a relative current flowing in the comma-free coils at the middle left portion and the middle right portion and thereby, adjusting a relative magnetic field in the left and right sides; and a vertical center raster mis-convergence adjusting portion, comprising variable resistance connected to the comma-free coils in parallel, and fixed resistance connected to a common contact point of the left and right comma-free coils and a moving electrode of the variable resistance.
It is desirable that the variable resistance connected to the comma-free coils in parallel, and fixed resistance connected to a common contact point of the left and right comma-free coils and a moving electrode of the variable resistance.
Further, an apparatus for correcting a mis-convergence and geometric distortion in a deflection yoke using a variable resistance, comprising a conical-shaped coil separator including a neck portion and a screen section; an upper horizontal deflection coil and a lower horizontal deflection coil installed to be electrically connected to each other at an upper and lower portions of inner periphery of the screen portion in the coil separator; a left vertical deflection coil and a right vertical deflection coil installed to be electrically connected to each other at an upper and lower portions of outer periphery of the screen portion in the coil separator; a conical-shaped ferrite core installed at outer periphery of the screen portion in the coil separator to enhance a magnetic field of the vertical deflection coil; a plurality of comma-free coils installed at the neck portion of the coil separator to be electrically connected to the vertical deflection coil for generating a pin-cushion magnetic field, thereby canceling a barrel magnetic field generated by the left and right vertical deflection coils; a distortion adjusting portion for correcting geometric distortion on a screen by adjusting a relative current flowing in the left and right vertical deflection coils and thereby, adjusting a relative magnetic field in the left and right sides; a first convergence adjusting portion for correcting a vertical mis-convergence on a screen by adjusting a relative current flowing in the comma-free coils at the middle left portion and the middle right portion and thereby, adjusting a relative magnetic field in the left and right sides; and a vertical center raster mis-convergence adjusting portion, comprising variable resistance connected to the comma-free coils in parallel, and fixed resistance connected to a common contact point of the left and right comma-free coils and a moving electrode of the variable resistance.
It is desirable that the variable resistance in the vertical center raster is in a range of from 5 to 10xcexa9.
Further more, an apparatus for correcting a mis-convergence and geometric distortion in a deflection yoke using a variable resistance, comprising a conical-shaped coil separator including a neck portion and a screen section; an upper horizontal deflection coil and a lower horizontal deflection coil installed to be electrically connected to each other at an upper and lower portions of inner periphery of the screen portion in the coil separator; a conical-shaped ferrite core installed at outer periphery of the screen portion in the coil separator to enhance a magnetic field of the vertical deflection coil; upper and lower left vertical deflection coils and upper and lower right vertical deflection coils wound around the ferrite core to be electrically connected for generating vertical deflection magnetic fields at the upper and lower portions; a plurality of comma-free coils installed at the neck portion of the coil separator to be electrically connected to the vertical deflection coil for generating a pin-cushion magnetic field, thereby canceling a barrel magnetic field generated by the left and right vertical deflection coils; a first convergence adjusting portion for correcting a vertical mis-convergence on a screen by adjusting a relative current flowing in the comma-free coils at the middle left portion and the middle right portion and thereby, adjusting a relative magnetic field in the left and right sides; and a vertical center raster mis-convergence adjusting portion, comprising variable resistance connected to the comma-free coils in parallel, and fixed resistance connected to a common contact point of the left and right comma-free coils and a moving electrode of the variable resistance.
It is desirable that the variable resistance in the vertical center raster is in a range of from 5 to 10xcexa9.
Further more, an apparatus for correcting a mis-convergence and geometric distortion in a deflection yoke using a variable resistance, comprising a conical-shaped coil separator including a neck portion and a screen section; an upper horizontal deflection coil and a lower horizontal deflection coil installed to be electrically connected to each other at an upper and lower portions of inner periphery of the screen portion in the coil separator; a left vertical deflection coil and a right vertical deflection coil installed to be electrically connected to each other at an upper and lower portions of outer periphery of the screen portion in the coil separator; a conical-shaped ferrite core installed at outer periphery of the screen portion in the coil separator to enhance a magnetic field of the vertical deflection coil; a plurality of comma-free coils installed at the neck portion of the coil separator to be electrically connected to the vertical deflection coil for generating a pin-cushion magnetic field, thereby canceling a barrel magnetic field generated by the left and right vertical deflection coils; a distortion adjusting portion for correcting geometric distortion on a screen by adjusting a relative current flowing in the left and right vertical deflection coils and thereby, adjusting a relative magnetic field in the left and right sides; a first convergence adjusting portion for correcting a vertical mis-convergence on a screen by adjusting a relative current flowing in the comma-free coils at the middle left portion and the middle right portion and thereby, adjusting a relative magnetic field in the left and right sides; a second convergence adjusting portion for correcting a horizontal mis-convergence on a screen by adjusting a relative current flowing in the comma-free coils at the upper portion and the lower portion and thereby, adjusting a relative magnetic field in the upper and lower sides; and a vertical center raster mis-convergence adjusting portion, comprising a first current adjusting resistance having one end connected to a contact point of a right vertical deflection coil and a left comma-free coil; a second current adjusting resistance having one end connected to a contact point of a right comma-free coil and a power supply source; a variable resistance connected to a common contact point of the left and right comma-free coils and a moving electrode of the variable resistance, having one end connected to the other end of the first current adjusting resistance and another end connected to the other end of the second current adjusting resistance.
It is desirable that the variable resistance in the vertical center raster is in a range of from 5 to 10xcexa9.
Further more, an apparatus for correcting a mis-convergence and geometric distortion in a deflection yoke using a variable resistance, the apparatus comprising: a conical-shaped coil separator including a neck portion and a screen section; an upper horizontal deflection coil and a lower horizontal deflection coil installed to be electrically connected to each other at an upper and lower portions of inner periphery of the screen portion in the coil separator; a left vertical deflection coil and a right vertical deflection coil installed to be electrically connected to each other at an upper and lower portions of outer periphery of the screen portion in the coil separator; a conical-shaped ferrite core installed at outer periphery of the screen portion in the coil separator to enhance a magnetic field of the vertical deflection coil; a plurality of comma-free coils installed at the neck portion of the coil separator to be electrically connected to the vertical deflection coil for generating a pin-cushion magnetic field, thereby canceling a barrel magnetic field generated by the left and right vertical deflection coils; a first convergence adjusting portion for correcting a vertical mis-convergence on a screen by adjusting a relative current flowing in the comma-free coils at the middle left portion and the middle right portion and thereby, adjusting a relative magnetic field in the left and right sides; and a vertical center raster mis-convergence adjusting portion, comprising a first current adjusting resistance having one end connected to a contact point of a right vertical deflection coil and a left comma-free coil; a second current adjusting resistance having one end connected to a contact point of a right comma-free coil and a power supply source; a variable resistance connected to a common contact point of the left and right comma-free coils and a moving electrode of the variable resistance, having one end connected to the other end of the first current adjusting resistance and another end connected to the other end of the second current adjusting resistance.
It is desirable that the variable resistance in the vertical center raster is in a range of from 5 to 10xcexa9.
Further more, an apparatus for correcting a mis-convergence and geometric distortion in a deflection yoke using a variable resistance, comprising a conical-shaped coil separator including a neck portion and a screen section; an upper horizontal deflection coil and a lower horizontal deflection coil installed to be electrically connected to each other at an upper and lower portions of inner periphery of the screen portion in the coil separator; a left vertical deflection coil and a right vertical deflection coil installed to be electrically connected to each other at an upper and lower portions of outer periphery of the screen portion in the coil separator; a conical-shaped ferrite core installed at outer periphery of the screen portion in the coil separator to enhance a magnetic field of the vertical deflection coil; a plurality of comma-free coils installed at the neck portion of the coil separator to be electrically connected to the vertical deflection coil for generating a pin-cushion magnetic field, thereby canceling a barrel magnetic field generated by the left and right vertical deflection coils;
a distortion adjusting portion for correcting geometric distortion on a screen by adjusting a relative current flowing in the left and right vertical deflection coils and thereby, adjusting a relative magnetic field in the left and right sides; a first convergence adjusting portion for correcting a vertical mis-convergence on a screen by adjusting a relative current flowing in the comma-free coils at the middle left portion and the middle right portion and thereby, adjusting a relative magnetic field in the left and right sides; and a vertical center raster mis-convergence adjusting portion, comprising a first current adjusting resistance having one end connected to a contact point of a right vertical deflection coil and a left comma-free coil; a second current adjusting resistance having one end connected to a contact point of a right comma-free coil and a power supply source; a variable resistance connected to a common contact point of the left and right comma-free coils and a moving electrode of the variable resistance, having one end connected to the other end of the first current adjusting resistance and another end connected to the other end of the second current adjusting resistance.
It is desirable that the variable resistance in the vertical center raster is in a range of from 5 to 10xcexa9.
Further more, an apparatus for correcting a mis-convergence and geometric distortion in a deflection yoke using a variable resistance, comprising a conical-shaped coil separator including a neck portion and a screen section; an upper horizontal deflection coil and a lower horizontal deflection coil installed to be electrically connected to each other at an upper and lower portions of inner periphery of the screen portion in the coil separator; a conical-shaped ferrite core installed at outer periphery of the screen portion in the coil separator to enhance a magnetic field of the vertical deflection coil; upper and lower left vertical deflection coils and upper and lower right vertical deflection coils wound around the ferrite core to be electrically connected for generating vertical deflection magnetic fields at the upper and lower portions; a plurality of comma-free coils installed at the neck portion of the coil separator to be electrically connected to the vertical deflection coil for generating a pin-cushion magnetic field, thereby canceling a barrel magnetic field generated by the left and right vertical deflection coils; a first convergence adjusting portion for correcting a vertical mis-convergence on a screen by adjusting a relative current flowing in the comma-free coils at the middle left portion and the middle right portion and thereby, adjusting a relative magnetic field in the left and right sides; and a vertical center raster mis-convergence adjusting portion, comprising a first current adjusting resistance having one end connected to a contact point of a right vertical deflection coil and a left comma-free coil; a second current adjusting resistance having one end connected to a contact point of a right comma-free coil and a power supply source; a variable resistance connected to a common contact point of the left and right comma-free coils and a moving electrode of the variable resistance, having one end connected to the other end of the first current adjusting resistance and another end connected to the other end of the second current adjusting resistance.
It is desirable that variable resistance in the vertical center raster is in a range of from 5 to 10xcexa9.